In cases of ED and hypogonadism, recent randomized controlled trials suggest that patients who are initially refractory to type V phosphodiesterase (PDE5) inhibitors (sildenafil, vardenafil, and tadalafil) can be rescued by the concurrent administration of testosterone with PDE5 inhibitors. The administration of testosterone alone, without PDE5 inhibitors, has also been shown to improve erectile function in hypogonadal men. Androgen deficiency has been shown to result in penile tissue atrophy, increased adipose tissue within the subtunical region, and severe venous leak resulting in ED. All of these effects can potentially be reversed by the administration of testosterone. A number of distinct pathways of the endocrine system lead to ED when functioning abnormally. Several studies show that hypogonadism of any cause is an uncommon cause of ED.

The role of testosterone and other androgens in the achievement and maintenance of penile erection is controversial due to the lack of standardization in defining low testosterone. A recent study found that the prevalence of “low testosterone” in men with ED was largely dependent on the accepted definition of this disease state. Reported prevalence increased from 7% to 47% for definitions of testosterone level less than 200 ng/dL versus less than 400 ng/dL, respectively.

The role of androgens in erectile physiology as demonstrated in the animal model is to potentiate the effects of neurologic and vascular/ endothelial mechanisms of erection. Although tumescence is possible with decreased testosterone, the quality of the erection may be diminished. Importantly, the efficacy of PDE5 inhibitors is greatly diminished in the absence of androgens. Furthermore, in rats, dihydrotestosterone is the primary androgen responsible for erectile physiology at the level of the endothelial cell. Mexican Viagra Online

This decline in serum testosterone level can be age-related or the result of hypogonadism of any cause. A recently published study evaluated the prevalence of both hypogonadism and depression in men presenting to an ED clinic. They also tested the correlation of hypogonadism and the presence of depressive symptoms. They indeed found hypogonadal men to be more likely to have overt depression scores compared to eugonadal controls. The authors derived the conclusion that depression symptoms are strongly associated with hypogonadism and that physicians should consider the evaluation of testosterone levels in men with overt symptoms of depression.